One application area of current spacecraft technology is the launching into orbit of various payloads, such as communication satellites and exploratory vehicles. For example, a Boeing Delta IV rocket may be used as a launch vehicle for a payload, such as a Eutelsat communications satellite. During the launching and separation processes (when the fairing is separated from the launch vehicle), the payload is typically subjected to significant amounts of shock and vibration stresses. The fairing is a structure that protects the payload from rain, lightning, winds, contamination and heating, until the launch vehicle reaches a very high altitude. The fairing separates from the launch vehicle when the heating rate on the payload is below a predetermined value. Under certain conditions, the transient shock and vibration energy experienced by the payload can exceed the design limits within the 100 to 300 Hz frequency range. The spacecraft is subject to high loads at lift-off, and again as the launch vehicle is subjected to atmospheric turbulence (e.g., at 35,000 to 40,000 feet) at the same time that the vehicle is subjected to its maximum dynamic external pressure (Max q). However, at the time of fairing separation, the loads on the spacecraft are very low.
Since the payload typically carries many sophisticated devices dedicated to the successful completion of a mission, it is important to limit the shock and vibration load energy imposed on the payload from the fairing separation processes. For this purpose, an interface shock and vibration isolation assembly is typically connected between the launch vehicle and the payload. This interface assembly generally incorporates some type of isolation assembly to reduce the shock and vibration impact on the payload. The isolation assembly may also be configured as the entire interface assembly between launch vehicle and payload.
As the demand increases for different types and sizes of payloads, the shock and vibration reduction requirements for isolation assemblies become ever more stringent. Therefore, a need exists to increase the shock and vibration absorption capabilities of spacecraft interface isolation assemblies. At the same time, it is desirable that the improved isolation assembly supports the payload at lift-off and Max q without significant change in the stiffness of the spacecraft supporting structure. In addition, it is generally desirable that an improved isolation assembly does not significantly increase the weight or size of the interface assembly. It is also generally desirable that an improved isolation assembly can be easily retrofitted into an existing spacecraft interface design.
Accordingly, it is desirable to provide a spacecraft interface isolation system with improved shock and vibration reduction capabilities, such that the improved isolation system does not significantly change the stiffness of the supporting structure. In addition, it is desirable for the improved isolation system to be a convenient mechanical retrofit for an existing system. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.